Grinding wheel truing apparatus



Patented Sept. 7, 1937 l [UNITED STATES 1 PATENT ol-Flcs tion'of Massachusetts Carl -G.@Flygare, Worcester, Mass., assigner to Norton Company, Worcester, Mass., a corpora- `Implication January 14,l masa-mi No. 59,004 14 claims. (Cl. 12s- 11) This invention relates to grinding machines, and more particularly to a grinding wheel truing apparatus 'for truing theoperative face of a grinding wheel in a roll grinding machine.

One of the'objects of this invention is to provide an improved apparatus forproducing a predetermined ciirved face orcrown on the operative face of a'grinding wheel, which is particularly adapted for grinding the crown on large rolls, such as are used in rolling mills. v

'A further object of this invention is to provide a simple, thoroughly practical truing apparatus in which an adjustable forming bar is utilized to cause lan approaching or receding movement of the truing tool` to true a predetermined curved 4face on the periphery of a grinding wheel. A furtherobject of this invention is to provide 'an improved means` for adjusting a grinding wheel `tru-ing apparatus to` obtain various curvatures-on and the scope of the 'application of'which will be indicated in the following claims.I

In the accompanying drawings in which is shown one -of the variouspossible embodiments of the mechanical features of this invention, Fig. 1 is a fragmentary side elevation ofthe improved grinding 4wheel truing 'apparatus mounted on the grinding machineand having parts `brokenaway Aand shown in section to more f clearly show the construction;

Fig. 2 isa rear'elevation of the wheel' truing apparatus and itssupport, taken approximately on the line 2-'7-2 of'Fig. 1, having 'parts broken away' to more clearly show the mounting of the truing attachment;

, Fig.. 3 is a` fragmentary elevation ofthe forming bar, illustrating the mounting ,Y and the adjustment of the forming bar;I

Fig. 41s a cross sectional view of the forming y 3- bar, taken approximately on the line l-l, of

, Fig. 5 is a fragmentary yside elevation, partly ,in section, vof a modication of the Aconstruction shown in Fig. 1; `and 55 Fig. Gfis a lfragmentarysectional view of `protected byy an adjustable wheelgguard II.

modified forming barvv for producing a concave crown on the grinding wheel.

As illustrated in the drawings, a fragment of a grinding machine has been illustratedycomi prising a transversely movable grinding wheel I0 which is supported on a transversely movable slide (not shown), as is common practice in the grinding machine art. The grinding'wheel ID is A longitudinally reciprocable work table I2 is(` mounted on the usualways on the base'of the machine, such as that shown in the prior Norton Patent No. 762,838 dated June 14, 1904, to which reference mayl be had for details of disclosure.

The table 'I2 is provided with a supporting sur-` I face,l I3 which is arranged to mate with a surface I4 on a footstock I5 which may be clamped-to the table I2 by means of a clamping block I6. lA stud I'I projects 'from the footstock I5 and passes through a clearance hole in the clampingV member I6 and is provided with a washer I8 Aand a clamping nut I!!` which serve to clampthe footstock I5 in position on the table I2.

' In the grinding lof a rollfor a rolling mill, it is frequently necessary to grind a predeterminedA crown on' the' periphery ofthe roll;` In order to obtain an emcient grinding action in forming a predetermined crown on theperiphery of a'roll being ground, it is desirable to provide a grinding wheel with an operating face whichiscrowned` tus is provided by which the wheel may be -readily truedtothe desired curvature,l A truing apparatus is mountedfjon the machine so that the grind- 'ing wheel I0 andthe roll being ground may' be Y traversed longitudinally relativeto eachother to I a truing position to true the peripheral face of the grinding wheel,A after which the grinding operation may be quicklyand readily resumed. In the preferred form of thisinvention, the truing apparatus `is mounted in axed position on the `footstocls Iii.'v A base or bracket 25 is held in xed `position on the footstock I5 Vby the screws 26 and 21. The bracket 25 is provided with two bosses 28 and 29 which extend toward the grind- "ing wheel. The boss 29 is provided with a bushing 30 having a tapered aperture 3|' which supports a center ,32; The boss 28 contains a vslidl able, non-rotatable sleeve which is held against rotation by a key 34 and is arrangedto slide longitudinally within an aperture 35 in the boss 28. The sleeve 33 is provided with a tapered aperture 36 which supports a center 31. In order that the center 31 may be adjusted toward and from the center 32, a manually adjustable hand wheel 40 is mounted on the outer end of a rotatable screw 4| which is screw threaded into a threaded aperture 42 within the sleeve 33. The end of the screw 4| and hand wheel 40 serve as end thrust members for the screw 4| which is rotatably supported in the plate 42 mounted on the end of the boss 28.

A truing tool supporting member 45 is provided with countersunk apertures 46 and 41 which are arranged to be engaged by the centers 32 and 31 to serve as a pivotal support for the truing tool supporting member 45. The bracket 25 is preferably located so that the axis of the centers 32 and 31 is parallel to the axis of the roll being ground and to the axis of the grinding wheel l0, so that the frame 45 may be swung at right angles to the surface of the grinding wheel l0 which is to be trued. 'I'he frame 45v is provided with an angularly disposed aperture 50 which is arranged to support a truing tool holder 5| carrying a diamond or truing tool 52 in the outer end thereof. 'Ihe truing tool holder 5| is arranged tobe clamped in adjusted position on the support 4,5 by means of a clamping screw 53 which may be actuated by a clamping handle 54.

The projecting boss 28 is preferably split so that the sleeve 33 may be clamped in adjusted position to hold the truing tool support 45 in adjusted position. As illustrated in Fig. 1, the boss 28 is provided with a radially extending slot 55. A clamping screw 56 passes through a clearance hole in the upperportion 51 and is screw threaded into the lower portion 58 so that when the adjusting knob 40 has been turned to adjust the supporting center 31 relative to its mating surface 46, the sleeve 33 may be rigidly clamped within the boss 28 to hold the parts in their adjusted position during the operation of the apparatus.

In order to limit the swinging movement of the support 45 so as to limit the movement of the truing tool or diamond 52 toward and from the periphery of the grinding wheel I0, a pin 60 passes through the truing tool support 45 and rides in an elongated slot 6| in a projection 62 of the bracket 25. The projection 62 extends through an aperture 63 in the truing tool support 45 and is arranged to slidably t between the bosses 64 and A65 on the truingtool support 45. l

To true the desired crown or curvature on the operative face of the grinding wheel, a means is provided for swinging the truing tool support toward and from the operative face of the grinding wheel to vcause the diamond or truing tool 52 to approach or recede from the wheel so as to generate a predetermined form thereon. In the preferred construction, a formingbar 10 is pivotally mounted on a stud 1| on the upper end of the truing tool supporting bracket 45. The operative face of the form 10 is preferably formed as a partial cylindrical surface, as indicated in Figs. 1 and 4. The forming bar 10 is held in place on a surface 12 on the upper end of the truing tool supporting bracket 45V by means of a pair of clamping blocks 13 and 14 which are held in place on the bracket. by means of screws 15, 16 and 11, 18, The forming bar 10 may be clamped in 'rigid engagement with the surface 12 of the truing tool support 45 by tightening the screws 15, 16 and 11, 18.

Y truing operation.

A follower roller is rotatably mounted on a stud 8| carried by a bracket 82 which is adjustably mounted on the wheel guard The bracket 42 is supported on a projection 83 of the wheel guard and may be clamped in adjusted position thereon by bolts 84, the heads of which slide in a longitudinally extending T-slot 85. The roller 80 is preferably adjusted longitudinally so that its axis of rotation is in alignment with the center of the wheel, that is it lies in a medial plane between the side faces of the grinding wheel.

The roller 80 preferably engages the surface of the form 10 at a point in alignment with the axis of adjustment of the forming bar 10. In the position of the parts as illustrated in Figs. 1 and 2, when the table I2 or wheel |0 are traversed longitudinally. the roller 80 will follow along an element of the partial cylindrical surface of the forming bar 10 and the truing tool 52 will generate a true cylindrical surface on the wheel |0.

In order to produce a crowned or curved operative face on the wheel I0, the forming bar may be adjusted or rotated about its pivot 1| so that the follower roller 80 instead of 'passing along an element of the cylindrical surface of the forming bar 10 will pass along a line at an angle thereto, thus causing the truing tool support 45 to be rocked about its supporting centers 32 and 31 to generate a predetermined curved face on the periphery of the wheel. To facilitate adjustment of the forming bar 10, its left-hand edge, as viewed in Fig. 3, is provided with gear teeth 80 which mesh with a pinion 9| carried by a stud 92. The bar 10 is unclamped by loosening the screws 15, 16, 11 and`18. 'I'he stud 92 may then be rotated t0 turn the pinion 8| to turn the gear segment to angularly adjust the forming bar 10 relative to its supporting surface 12. To facilitate adjustment of the forming bar 10 to the desired extent in either direction, the left-hand edge of the forming bar 10, as viewed in Fig. 3, is provided with a graduated scale which registers with a zero point 96 on the clamping block 13, so that the bar 10 may be readily adjusted to the desired extent to cause the desired swinging movement of the truing tool support 45 to move the truing tool or diamond 52 toward or from the wheel axis as the wheel and Work are reciprocated longitudinally relative to each other to generatey a predetermined crowned or curved face on the periphery of the grinding wheel.

A spring |00 is interposed between the truing tool supporting member 45 and the bracket 25 and serves to maintain the forming bar 10 in operative contact with the follower roller 80 during the The spring |00 is held within an aperture 0| in the member' 45 and has its other end bearing against the bracket 25 so as to exert a pressure on the member 45 tending to move it in a counterclockwise direction.

The follower roller 80 is arranged to engage the partial cylindrical surface 10 of the forming bar along the element of said surface which is.

at right angles to the axis of adjustment of the forming bar 10 so that when the forming bar 10 is arranged with its elements parallel to the axis ofthe grinding wheel, the follower roller 80 will travel along an element of the surface 10 and generate a true cylindrical surface on the Operative face of the grinding wheel. The axis of adjustment of the forming bar 10 is arranged at substantially right angles to a plane passing through the axis of the centers 32 and 31 and tangent to the partial cylindrical surface 10 of the forming bar. When the roller 80 and the the `truing tool 'support 45.

A4- modification ofthe apparatus above de- -scribed has been illustrated in Fig. 5, in which form 10 engage each other, as above described, a longitudinal traversing movement between the wheel |0 and tablev I2 will generate a true cylinder of revolution on the periphery of the grinding If the vforming bar '|0 is `angularly adjusted about its. axis of support, then the roller 80 will contact with thecylindrical surface -10 along a line at an angle to an element of said surface so that when the vroller 80 and forming bar 10 are traversed longitudinally relative to each other, a rocking movement is transmitted to the truing tool support and the truing tool 52 will generate a predetermined convex curve on the operative peripheral face of the wheel. The spring |00 normally moves the truing tool carrier 45 in a4 counterclockwise direction (Fig. 1) and maintains the pin 60 in engagement with the forward end of the elongated slot 6|l during the grinding operation. 1n order to facilitate moving thel truing apparatus into an operative position, a knob is mounted on the `outer end of a rod |5| winch is pivotally connected to a stud |52 on the truing tool supporting bracket 45. The rod |5| is loosely jou'maled in a bracket |53 which is fixed on the upper surface ofthe footstock I5. In order that the parts of the mechanism may be properly adjusted so that the follower roller 00 engages the forming bar 10 at its axis of adjustment when the diamond or truing tool 52 is in the center of the grinding wheelv I0, it is desirable'to provide an index device.l "In order to facilitate setting up the truing apparatus to insuretheroller 60 contacting with the form 10 at the-axis of adjustment of the form when the truing tool 52 isl in a central position on vthe Wheel face, an Iindex finger |54 is mounted on the bracket |53 and is arranged in the path of a zero mark |55 on the rod I5'. When the zero point |55 coincides with .theindexnger |54, the forming'bar 10 is in proper relation with its pivot lpoint so that the roller 80 will engage the forming bar 10 at its axis of adjustment when the diamond is in a central positionA on the operative vface of the wheel.

vDuring the grinding operation, as the grindying wheel is reduced in' size dueto wear and truing, it is necessary' at intervals to ladjust'the wheel guard toward thefperipheral face of the roller support 82 and is arranged in the path of a graduated scale formed on thesurface |6| of a forming bar |25 is pivotally mounted on a stud wheel guard] I'. The forming bar |25 is provided with a'partial cylindricalsurface |28 which is engaged by 'a rotatable follower roller |29 carried by a stud |30 which is supported on the'truing tool carrying'member 45. The roller |29 and itssupporting stud 30'are preferably carried by an adjustable member |3|l which' is slidably mounted within an aperture |32 in the upper end of'the bracket 45 and v is slidably keyed thereto by a key |33. To facilitate adjustment ofthe follower roller |26,` a manually operable knob' |35 is'mounted on the outeriend of a rotatable adjustingscrew. |36 `which is screw threaded into a nut |31 fixed to the arm 4 5. The

inner` ena of the' screw-13s is provided with a reducedv ena portion laziwhieio nts within a cor- 3 member |3|. 'I'he reduced portion |38 is provided with a groove' |40 by which the screw is rotatably secured to the slidable member |3| by means'of a pin |4|f whichpasses'through the slide |3| and engages the groove |40 in the portion |30 of the Yscrew |36. By rotating theA knob |35, the position of the follower roller |20 may be adjusted to set up the device as desired.

The disclosure in the drawings, Figs. 1 to 5 inclusive, and the above description in the speciilcation relate to a truing apparatus for truing a convex crown on the operative face of a grinding wheel.- Thisinvention, however, is equally applicable for truing a concave ycrown ,on the periphery of the wheel, as will be seenin the modification illustrated in Fig. 6. A forming bar I6| has been illustrated in the drawings which may be pivotally mounted .,onthefupper portion of the truing tool support 145 in .the same manner as illustrated forrthe bar .10. Therforming bar |6| is provided with-a concave curved lface |62 which is formed as a partial cylinderzof revolution. This curved face `|62 is arranged to function inthe same manner as the convex forming bar .10 shownin Figs. 1 to 5i The follower roller 00 engages the concave Vcurved surfaceulGZ, serving to transmit motion to thevtruing tool support 45 to cause a concave operative face to -be produced on the grinding wheel. As in the case of the previously described construction, if

the elements of the partial cylinder of revolution are parallel to the axis of the.- grinding wheel andthe axis of the truing tool-"support, then vwhen the grinding wheelh and the work support areA traversed longitudinally relative to each other, the follower roller 80 will travel along an elementof the concave curved surface |62 of the forming bar and produce a -true cylindrical surface on the periphery of the wheel. If

' the forming bar |6| is adjusted angularly rela-.-

tive to the truing tool supporting member 45, thenthe follower roller 80 will travel along the line across the face of the partial cylinder of revolution which is at an angle to an element of said surface so as to cause a rocking movement the grinding wheel.v

Similarly, the bar 10 may be replaced by a forming bail having an irregular contourwhich` it is desired to produce von the periphery of the grindingwheel, and this forming bar will-transmit` a rocking motion of the truingtool support 45`as the work support and the grinding `wheel are traversed longitudinally relative to each other to produce the desired and predetermined forni on the grinding wheel |0.

` AIn setting up the apparatus for truing acurved fa'ce on .the periphery of the wheel, the table I2 or the grinding wheell I0, as the case vmaybe, isl

'traversed 'beyond a normal grinding' stroketo tion with the grinding wheel. When the forming bar 'i0 approaches the roller '80, the knob` |50 is |2 are moved longitudinally" relative ing tool 52 is in a centralpositlon'on the wheel face tov be trued. The truing tool 5|l is previouslyl pulled 4toward the right, as viewed in Fig. 1, to "swing the truing tool vsupport 45 in a clockwise ldirection so that the roller 0 0 will pass over `the vcdge'of'the forming bar A'||l. The wheel |0 and table to. each other until the'index nger `|60 coincides with a zero reading on the graduated scale on the surface |6|, indicating that the truwithdrawn toward the right, as'viewed in Fig. 1, to an inoperative position. 'I'he wheel slide carrying the grinding wheel I0 and the wheel guard Il and also the follower roller is then moved toward the right, as viewed in Fig. l, until the zero point |55 on the rod 15| coincides with the index finger |54, at which point the roller 80 engages the partial cylindrical surface 1D of the forming bar at a point coinciding with the axis of adjustment of the bar 10. The truing tool clamping handle 44 is then released and the truing tool 52 moved toward the left until it touches the peripheral surface of the grinding wheel, at which point the clamping handle 54 is then locked to hold the truing tool 52 in adjusted position on the truing tool support 45. If it is desired to produce a true cylindrical surface on the wheel being trued, the form 10 is allowed to remain in the position of the parts illustrated in Figs. 1 and 3. If ,it is desired to true a convex crown on the periphery of the wheel, the form 10 is adjusted angularly relative to its support by first loosening the screws 15, 16, 11 and 18 and then turning the stud 92 to rotate the forming bar 10 on its supporting stud 1I to the desired angular position relative thereto. The forming bar 10 may be adjusted angularly to a greater or lesser extent, depending upon the curvature desired to be produced on the peripheral surface of the wheel. When the proper adjustment of the form has been made, the form is then clamped rigidly in position by tightening the screws 15, 16, 11 and 18. The table I2 or the grinding wheel I0 may then be traversed longitudinally to cause a relative traversing movement between diamond 52 and the wheel l0. During this movement, the roller 80 will travel across the partial cylindrical surface 10 along a line at an angle to an element of said surface and will cause the truing tool support 45 to rock toward and from the wheel axis so as to produce a corresponding movement of the truing tool 52 toward and from the wheel face to generate a predetermined curved face thereon.

It will thus be seen that there has` been provided by this invention apparatus in which the various objects hereinabove set forth together with many thoroughly practical advantages are successfully achieved. As many possible embodiments may be made of the above invention and as many changes might be made in the embodiment above set forth, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in alimiting sense.

I claim:-

1. A grinding wheel truing apparatus for a grinding machine having a rotatable grinding wheel anda truing tool which are movable longitudinally and transversely relative to each other, a movable support for said truing tool, means to adjust the position of the truing tool relative to said support, meansA including an adjustably mounted cylindrical forming bar, a pivotal support for said bar which is arranged at right angles to the axis of said cylindrical surface, a follower to cause a transverse movement of said support, and means to angularly adjust the position vof the cylindrical form on its pivot so that the line of contact between the forming bar and the follower roller during the longitudinal traversing movement is in a path at an angle to an element of the surface of the forming bar to cause a transverse movement of said support when the grinding wheel and truing tool are 4moved longitudinally relative to each other to true a predetermined curved face on the grinding wheel.

2. A grinding wheel truing apparatus for a grinding machine having a rotatable grinding wheel and a truing tool which are movable longitudinally and transversely relative to each other, a movable support for said truing tool, an adjustably mounted forming bar having a partial external cylindrical surface thereon, a pivotal support for said bar which is arranged at right angles to the axis of said cylindrical surface and passing through said axis, a follower cooperating therewith to cause a transverse movement of said truing tool support, and means to angularly adjust said external cylindrical forming surface on its pivot so that an element thereof lies at an angle to the path of movement between the grinding wheel and truing tool to cause a transverse movement of said support to true a predetermined curved face on the grinding wheel.

3. A grinding wheel truing apparatus for a grinding machine having a rotatable grinding wheel and a truing tool which are movable longitudinally and transversely relative to each other, a movable support for said truing tool, an adjustably mounted forming bar having a partial internal cylindrical surface thereon, a pivotal support for said bar which is arranged at right angles to the axis of said internal cylindrical surface and passing through said axis, a follower cooperating therewith to cause a transverse movement of said truing tool support, and means to angularly adjust said internal cylindrical forming surface on its pivot so that an element thereof lies at an angle to the path of movement between the grinding wheel and truing tool to cause a transverse movement of said support to true a predetermined curved face on the grinding wheel.

4. A grinding wheel truing apparatus for a grinding machine having a transversely movable rotatable grinding wheel, an adjustable wheel guard surrounding said wheel and movable therewith, and a truing tool which are movable longitudinally and transversely relative to each other, a movable support for said truing tool, a forming bar having a a partial cylindrical surface and a follower cooperating therewith, one of which is mounted on the support and the other on the wheel guard to cause a transverse movement of said support when the grinding wheel and truing tool are moved longitudinally relative to each other, means to angularly adjust the forming bar so that the axis of the cylindrical surface is at an angle to the longitudinal movement between the wheel and truing tool to true a predetermined curved face on the grinding wheel.

5. A grinding wheel truing apparatus for a grinding machine having a transversely movable rotatable grinding wheel, an adjustable wheel guard surrounding said wheel and movable therefwith, and a truing tool which are movable longitudinally and transversely relative to each other, a movable support for said truing tool, a forming bar having a partial external cylindrical surface and a follower cooperating therewith, one of which is mounted on the support and the other on the wheel guard to cause a transverse movement of said support when the grinding wheel and truing tool are moved longitudinally relative to each other, means to angularly adjust the forming bar so that the axis ofthe cylindrical surface is at an angle to the longitudinal movement between the wheel and truing tool to true a prewheel.

of `which is mounted on the support and the other on the Wheel guard to cause a transverse movement of said support when the grinding wheel and truing tool are moved longitudinally relative to eachother, means to angularly adjust the forml v lngfbarso that the axis of the cylindrical surface is atan angle to the longitudinal movementbetween the wheel and truing tool to true a predetermined internal curved face on the grinding wheel.

'7a. A grinding wheel truing apparatus for truing a curved face on a rotatable grinding wheel,

` comprising a. rotatable grinding wheel, a frame,

a .truing tool support, pivotal connections between the frame and truing tool support, the axis of said pivotal connection being parallel to the axis of the grinding wheel and work support so that the truing tool support may swing toward and from the periphery of the grinding wheel, a truing tool adjustably mounted on said support, -a forming bar having a partial cylindrical surface thereon which is carried by said support and arrangedy so that the axis.` of the cylindrical surface is at an angle to the longitudinal lmovement between. the wheel and truing tool, and a follower roller adjustably mounted on the wheel guard and arranged to operatively engage the cylindrical form-- ing bar' so as to transmit a rocking motion to the truing tool support when the work support and the grinding wheel are reciprocated longitudinally relative to each other to generate a predetermined curved face on the periphery of the grinding wheel. ,d

8. A grinding wheel truing apparatus for truing a curved face on a rotatable grinding wheel, comprising a rotatable grinding wheel, a frame, a truing tool support, pivotalconnections between the frame and truing tool support, the axis of said pivotal connection being parallel to the axis of the grinding wheel and work support so that the truing tool support may swing toward and from the periphery of the grinding wheel, a truing tool adjustably mounted onsaid support, 'a forming bar having a partial cylindrical surface thereon which is carried by said wheel guard and arranged so that the axis of the cylindrical surface is at an angle to the longitudinal movement between the wheel and truing tool, and a follower roller adjustably mounted on the support and arranged to operatively engage the cylindrical forming bar so as to transmit a rocking motion to the -truing tool support when the work support andthe grinding wheel are recipro'cated longitudinally relative to each other to generate a predetermined curved face on the periphery of the grinding wheel.

9. A grinding'wheel truing apparatus for truing a curved face on a rotatable grinding wheel,

comprising a rotatable grinding wheel, a wheel guard therefor, a truing apparatus base, a vertically arranged truing tool support, pivotal connections between the base and truing tool support,

the axis of said pivotal connection being parallel to the axis of the grinding wheel and work support so that the truing tool support may swing toward and from the periphery of the grinding wheel,

a truing .tool adjustably mounted on said support,

a forming bar having a partial external cylindrical surface thereon which is carried by said support land arranged so that the axis of the cylindrical surface is at an angle to the longitudinal movement between the wheel and truing tool, a follower roller adjustably mounted on said wheel guard `and arranged to operatively engage said forming bar so as to transmit a rocking motion to the truing tool -support when the truing tool and the grinding wheel are reciprocated longitudinally relative to each other to generate a predetermined convex curved face on thel grinding wheel.`

. 10. A grinding wheel truing apparatus for truing a curved face on a rotatable grinding wheel, comprising a rotatable grinding wheel, a wheel guard therefor, a truing apparatus base, a vertically arranged truing tool support, pivotal connections between the base and truing tool support,

the axis of said pivotal connection being parallel tothe axis of the grinding wheel and work support so that the truing toolsupport may swing toward and from the 'periphery of the grinding wheel, a truing tool adjustably mounted on said support, a forming bar having a partial internal cylindrical surface thereon which is carried by said support and arranged so vthat the axis of the cylindrical surface is at an angle to the longitudinal movement between the wheel and truing tool, 'a follower roller adjustably mounted on said .wheel guard and arranged to operatively engage. said forming bar so as to transmit a rocking motion to the truingv tool support when the/truing tool and the grinding wheel are reciprocated longitudinally relative to each other to generate a predetermined concave curved face on the grinding wheel. Y

l1.. A grinding wheel truing apparatus for truing a curved face on a rotatable grinding wheel, comprising a transversely movable rotatable grinding wheel, a wheel guard therefor, a frame, a truing tool support pivotally mounted on said frame, said pivotal connections being parallelto the axis of the grinding wheel so that the truing tool may swing towardand from the operative face of the wheel, a truing ,tool adjustably mounted on the support, a forming bar having a partial internal cylindrical surface thereon which is carried by said wheel-guard and arranged'so that the axis of the cylindrical surface is at an angle to the longitudinal movement between the wheel and truing tool, a follower roller adjustably mounted on the support and arranged to operatively engagesaid internal cylindrical surface so as to transmit a rocking motion to the truing tool support when the work support and the grinding wheel are reciprocated longitudinally relative to each other iso generate a predetermined concave curved face on the grinding wheel.

12. A grinding wheel truing apparatus for truing a curved face on a rotatable grinding wheel, comprising a transversely movable rotatable grinding wheel, a wheel guard therefor, a frame, a truing tool support pivotally mounted on said frame, said pivotal connections being parallel to the axis of the grinding wheel so that the truing tool may swing toward and from the operative face of the wheel, a truing tool adjustably mounted on the support, a forming bar having a partial external cylindrical surface thereon which is carried by said wheel guard and arranged so that the axis of the cylindrical surface is at an angle to the longitudinal movement between the wheel and truing tool, a follower roller adjustably mounted on the support andarranged to operatively engage said external cylindrical surface so as to transmit a rocking motion to the truing tool support when the work support-and the grinding Wheel are reciprocated longitudinally relative to each other to generate a predetermined convex curved face on the grinding wheel.

13. A truing apparatus of the type covered in claim 7 in which the operative face of the forming bar is formed as a partial internal cylindrical surface, and means to angularly adjust the position of the forming bar relative to its support so that when the grinding wheel and work support are reciprocated longitudinally, the follower roller will travel across said internal cylindrical surface at an angle to an element of said surface so as to vrocli; the truing tool toward and from the grinding wheel to generate a predetermined concave curved face on the grinding wheel.

14. A truing apparatus of the type specified in claim '7 in which the operative face of the forming bar is formed as a partial external cylindrical surface, and means to angularly adjust the position of said forming bar relative to its support so that the follower roller will travel across the external cylindrical surface at an angle to an element of said surface so as to rock the truing tool toward and from the grinding wheel axis during the longitudinal movement between the Wheel and truing tool to generate a predetermined convex curved face on the grinding wheel.

CARL G. FLYGARE. 

